This invention relates to magnetoresistive thin films and to devices having magnetoresistive elements for magnetic data storage, particularly in magnetic random access memory arrays.
Sun et al. U.S. Pat. No. 5,792,569 describes a tri-layer thin film magnetoresistive device having doped perovskite manganate thin films as ferromagnetic elements, separated by a barrier layer.
Parkin U.S. Pat. No. 5,801,984 describes a magnetic tunnel junction device, including a high coercivity fixed ferromagnetic multilayer structure and a single free ferromagnetic layer, separated by an insulating tunnel barrier layer. The fixed ferromagnetic multilayer is made up of two layers, a first ferromagnetic layer with a coercivity substantially higher than the applied field, and a thin ferromagnetic interface layer located between and in contact with the insulating tunnel barrier layer. The material of the first ferromagnetic layer of the multilayer can have low magnetization and thus poor spin filtering, and the interface layer is said to provide spin filtering.
MRAM constructs are needed, which are manufacturable and which have enhanced magnetoresistance, that is, which enhance the signal difference between the 0 and 1 states of the cell.